1) Gently mix the ingredients together, be careful not to break up the tomatoes.
2) Place tomatoes skin side down on a baking tray lined with grease proof paper. Save the oil and herb mixture that is left over.
3) Roast the tomatoes in the oven at 120c for around 4 hours, turning the tomatoes every hour till they are mostly dry but still a bit juicy.
4) Remove the tomatoes from the baking tray and toss with the herb and oil mixture saved from the first step.